1. Field of the Invention
The present invention relates to a printing device for a toroidal-shaped body and a printing method by using the same. More specifically, the present invention relates to a printing device which can effectively print indications such as letters, patterns, logo marks, numerals, and bar codes on the side portions of a toroidal-shaped body such as a tire, a tube, a roll, or the like.
2. Description of the Related Art
For example, as a method of printing white logo marks or the like on the side portions of the tire, there have been proposed a printing method of using a silk screen, a heat-printing method, a template printing method, a printing method of using a rubber-pad, and the like.
In the printing method of using a silk screen, as printing is usually carried out by using a cloth spread on a flat surface, it is difficult to print indications or the like on a curved surface (where printing is to be carried out) on the side portions of the tire.
In the heat-printing method, as a letter plate made of rubber on which a rubber paste has been applied is set on the surface of the tire and the rubber paste is vulcanized to thereby be converted into a rubber elastic body, there is a problem that, due to the heat during the vulcanization of the tire, organic fibers inside of the tire are subjected to heat-caused deterioration or heat-caused shrinkage, resulting in a decrease in strength of cords and the deterioration of tire performance.
In the template printing method, it is difficult to fit a template to a curved surface on which printing is to be carried out, such as the side portion of the tire, without forming any gap between the template and the curved surface. Further, there is a problem that ink spray-coated by a spray gun onto a surface on which printing is to be carried out (which surface will be referred to as the xe2x80x9cprinting surfacexe2x80x9d hereinafter) tends to blur at peripheries of letters or the like which have been engraved in the template, so that the peripheries of the printed letters or the like blur, resulting in unsatisfactory clearness.
In the printing method of using a rubber pad, there is a problem that, when a plurality of letters is printed on each side portion of the tire, it takes time to turn the tire over or a problem that, due to the use of ink dissolved in a solvent, ventilation is necessary and constant attention must be paid to keep the operation away from fire.
In view of the aforementioned facts, an object of the present invention is to solve problems involved in a conventional art and provide a printing device and a printing method capable of effectively printing clear indications on the side portions of a toroidal-shaped body such as a tire.
A first aspect of the present invention is a printing device, comprising: a support means for supporting a toroidal-shaped body; a plurality of transfer film supply means for supplying a transfer film, on the surface of which ink has been applied, to portions in the vicinities of the toroidal-shaped body, the ink exhibiting thermal transferability when heated; and a plurality of transfer means, disposed so as to correspond to the transfer film supply means, for heating the transfer film while pressing the ink applied surface of the transfer film onto a surface of the toroidal-shaped body.
In accordance with the first aspect of the present invention, in the aforementioned printing device, the toroidal-shaped body such as a tire is supported by the support means. And, the transfer film supply means supplies the transfer film onto, for example, the side portions of the toroidal-shaped body.
The transfer means heats the transfer film and presses the ink applied surface of the film onto the surface of the side portion of the tire. Ink is heated to generate transferability, is subjected to a pressing force, and thereby transferred onto the surface of the toroidal-shaped body.
For example, when logo marks are formed with ink beforehand and transferred onto the surface of the toroidal-shaped body, the logo marks are formed (printed) on the surface of the toroidal-shaped body.
In the present invention, since liquid ink is not used in printing, clear indications can be obtained without blurring.
Since there are provided a plurality of the transfer film supply means and a plurality of the transfer means, printing can be carried out simultaneously at a plurality of positions of the toroidal-shaped body.
In a second aspect of the present invention, the support means has a pressure imparting means for imparting pressure to the surface at the opposite side of a printing surface on which printing is to be carried out, of the toroidal-shaped body.
In accordance with the aforementioned second aspect of the present invention, in the printing device, the support means supports the toroidal-shaped body, and imparts pressure to the surface at the opposite side of the printing surface of the toroidal-shaped body.
When the transfer means presses the transfer film onto the side portion which constitutes the printing surface of the toroidal-shaped body, in a state in which pressure is not being imparted to the surface at the opposite side of the printing surface of the toroidal-shaped body, if the toroidal-shaped body is flexible, the side portion is easily deformed so that the ink applied surface of the transfer film may fail to contact the printing surface or may not be pressed onto the printing surface under an appropriate pressure.
However, in a case in which pressure is imparted to the surface at the opposite side of the surface on which printing is to be carried out of the toroidal-shaped body, when the transfer means presses the transfer film onto the side portion of the toroidal-shaped body, the side portion is prevented from deforming, the ink applied surface of the transfer film is reliably made to contact with the surface on which printing is to be carried out of the toroidal-shaped body, and thereby pressed to the surface on which printing is to be carried out under appropriate pressure.
As a result, in accordance with the second aspect of the present invention, ink can reliably be transferred onto the surface on which printing is to be carried out of the toroidal-shaped body.
A third aspect of the present invention is the printing device, including: a storage section for storing a plurality of toroidal-shaped bodies; and a conveying means for supplying the toroidal-shaped bodies stored in the storage section to the support means and for discharging the toroidal-shaped bodies for which printing has been completed from the supporting means.
In accordance with the third aspect of the present invention, the conveying means supplies the toroidal-shaped bodies stored in the storage section to the support means. The toroidal-shaped bodies for which printing has been completed are discharged by the conveying means from the support means.
A fourth aspect of the present invention is the printing device in which the support means includes a detection means for detecting a specified position of the toroidal-shaped body, and positions the toroidal-shaped body at a transfer position, at which ink-transfer is to be performed, on the basis of the specified positions detected by the detection means.
In accordance with the fourth aspect of the present invention, in the printing device, a specified position of the toroidal-shaped body is detected by the detection means. In the case of a tire, preferable examples of such a specified position include indications such as rotation marks which can be detected by an optical sensor, a TV camera, and the like.
On the basis of the results from the detection means, the support means positions the toroidal-shaped body at a transfer position at which ink-transfer is to be performed.
As a result, the aforementioned indications can be printed at predetermined positions based on the specified position of the toroidal-shaped body.
A fifth aspect of the present invention is the printing device, wherein the toroidal-shaped body is a tire rim assembly in which a tire is attached to a rim, and the support means supports the rim.
In accordance with the fifth aspect of the present invention, the rim of the tire rim assembly which constitutes the toroidal-shaped body is supported by the support means so that printing can be carried out, for example, on the side portion of a tire.
A sixth aspect of the present of the present invention is a printing method which comprises steps of imparting pressure to the surface at the opposite side of a surface on which printing is to be carried out, of a toroidal-shaped body; pressing a transfer film being in a state of being heated and having ink that generates transferability due to heating on the surface thereof, to the printing surface on which printing is to be carried out, the surface at the opposite of the printing surface being under a pressure; and thereby transferring the ink of the transfer film onto the surface on which printing is to be carried out.
In accordance with the aforementioned sixth aspect of the present invention, ink that generates transferability due to heating is transferred to the printing surface on which printing is to be carried out, by pressing a transfer film in a state of being heated to the printing surface whose opposite-side surface being under a pressure.
A seventh aspect of the present invention is the printing method further comprising a step of simultaneously transferring the ink of the transfer film onto a plurality of positions of the toroidal-shaped body.
In accordance with the aforementioned seventh aspect of the present invention, ink of the transfer film is simultaneously transferred onto a plurality of positions of the toroidal-shaped body.
An eighth aspect of the present invention is the printing method further comprising a step of disposing the transfer film such that the transfer film faces each of axial direction side surfaces of the toroidal-shaped body and then simultaneously transferring the ink of the transfer film on both of the axial direction side surfaces of the toroidal-shaped body.
In accordance with the eighth aspect of the present invention, the transfer film is disposed so as to face each of the axial direction side surfaces of the toroidal-shaped body, and ink of the transfer film is simultaneously transferred on both axial direction side surfaces of the toroidal-shaped body. Therefore, printing can be effectively carried out on both axial direction side surfaces of the toroidal-shaped body.
A ninth aspect of the present invention is the printing method further comprising a step of sequentially shifting a strip-shaped transfer film and transferring said ink onto said transfer film.
In accordance with the aforementioned ninth aspect of the present invention, when another toroidal-shaped body is positioned at the transfer position, in place of the toroidal-shaped body having ink already transferred thereon, after ink of the transfer film has been transferred onto the toroidal-shaped body, the transfer film is shifted such that a portion of the transfer film having ink thereon faces the another toroidal-shaped body and another printing or transfer process can be carried out.
When a sheet type transfer film is used, the transfer sheet must be changed for each toroidal-shaped body so that the changing operation becomes troublesome. On the other hand, in the printing method according to the ninth aspect of the present invention, the printing process can be repeated or continuously performed for a plurality of toroidal-shaped bodies only by shifting the transfer film, whereby the operation is made easy.
A tenth aspect of the present invention is the printing method wherein the toroidal-shaped body is a tire rim assembly in which a tire is attached to a rim and the method further comprising a step of carrying out a transfer in a state in which internal pressure is imparted into the tire.
In accordance with the tenth aspect of the present invention, printing can be carried out, for example, on the side portion of the tire of the tire rim assembly.
Further, when internal pressure is imparted into a tire, rigidity of the side portion of the tire becomes high. Accordingly, when the transfer film is pressed to the side portion of the tire, ink can reliably be transferred onto the tire side portion.